Direct welding of silicon carbide and fused silica using femtosecond lasers: Effects of repetition rate and focal depth

Silicon carbide (SiC) is a wide bandgap semiconductor known for its durability and high performance. These properties make it an ideal material for advanced applications. In this study, a femtosecond laser with a wavelength of 1030 nm was employed to weld SiC to fused silica directly. The key experimental variables examined were the laser repetition rate (100, 300, 1000 kHz) and focal depth. Energy-dispersive spectroscopy (EDS) was used to analyze the elemental distribution, revealing a spatial gradient in composition. This indicated the mixing and diffusion of elements between the two materials under focused laser energy. Separation specimens showed that fractures occurred primarily within the fused silica near the welded region, where island-like structures formed as fused silica adhered to the SiC surface.